Sampling device for rotary cone vacuum dryer

ABSTRACT

A SAMPLING DEVICE FOR REMOVAL OF PRODUCT TEST SPECIMENS FROM A ROTATING VACUUM DRYER IN WHICH A SPIRAL CHANNEL AXIALLY EXTENDS THROUGH ONE OF THE HOLLOW TRUNNIONS HELD IN THE USUAL ROTARY GLAND SYSTEM. ROTATION OF THE SCREW CHANNEL EXTRACTS A PORTION OF THE PRODUCT MATERIAL AND DEPOSITS IT IN A VALVE WITHOUT INTERRUPTING ROTATION OF THE DRYER OR BREAKING THE VACUUM THERETO OR DISCONTINUING ANY PHASE OF THE CYCLE OF OPERATIONS.

Jan. 12,1971" 7 b, P. SWEENEY ETAL 3,554,038

SAMPLING DEVICE FOR ROTARY CONE VACUUMM DRYER Filed Dec. 16, 1968 r 4 Sheets-Shet 1 DAN/EL I? SWEENEY WERNER CI HAAS HAROLD R. POWELL ATTORNEY- Jan. 12, 1971 D, p SWEENEY ETAL 3,554,038

SAMPLING DEVICE FOR ROTARY CONE VACUUMM DRYER FiledDecQlG, 1968 4 Sheets-Sheet 2 .um Q

wy w tk r PHD "In,

NHQQ

Jan. I ip W Y ET AL 3,554,038

SAMPLI NG DEVICE FOR ROTARY CONE VACUUMM DRYER Filed Die c. 16, 1968 4 Sheets-Sheet s INVENTORS DAN/EL R. SWEE/V'y WERNER C. HAAS HAROLD R. POWELL ar/$7M ATTORNEY Jan. 12, 1971 p E N ETAL 3,554,038

' SAMPLING DEVICE FOR ROTARY com: VACUUMM DRYER mud Dec. 16, 1968 V 4 Shgets-Sheetfl &

DAN/EL P. SWEENEY WERNER C. HAAS HAROLD R; POWELL ATTORNEY United States Patent 3,554,038 SAMPLING DEVICE FOR ROTARY CONE VACUUM DRYER Daniel Patrick Sweeney and Werner Carl Haas, Philadelphia, and Harold R. Powell, King of Prussia, Pa., assignors to Pennsalt Chemicals Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Dec. 16, 1968, Ser. No. 784,115 Int. Cl. G01n 1/100 US. Cl. 73-424 8 Claims ABSTRACT OF THE DISCLOSURE A sampling device for removal of product test specimens from a rotating vacuum dryer in which a spiral channel axially extends through one of the hollow trunnions held in the usual rotary gland system. Rotation of the screw channel extracts a portion of the product material and deposits it in a valve without interrupting rotation of the dryer or breaking the vacuum thereto or discontinuing any phase of the cycle of operations.

This invention relates to rotary vacuum dryers, and more particularly relates to a means for removing test samples or specimens of product being dried in rotating double-cone vacuum dryers without interrupting the rotation, without breaking vacuum, or without discontinuing any phase of the operating procedure.

As is well known, rotating drum or cone vacuum dryers are basically batch dryers, the vacuum being employed in operations (1) when low solids temperatures must be obtained because excessive heat would cause damage to the product or change its properties, (2) where air would combine with the product when it is heated so as to cause oxidation or explosive conditions, (3) where solvent recovery is required, and (4) where materials must be dried to extremely low moisture levels. The double-cone dryer consists of a jacketed shell, including a central cylindrical portion with outwardly directed conical walls, which is horizontally mounted for rotation transverse to the cylindrical-conical axis. The sloping walls of the cones permit more rapid emptying of solids when the dryer is in stationary position. The vacuum is applied to the interior of the shell through hollow trunnions mounted within suitable rotary packing glands, the latter also being utilized for admission and removal of the heating medium from the jacket.

During processing of the material being dried in such dryers, it is frequently desirable and necessary to determine the moisture content and/or other properties so as to be able to evaluate the degree of completion of the operation. Previous methods of extracting test samples or specimens of material from the interior required stopping of the dryer and removing the test samples through a series of air locks. As is apparent, such a procedure would likely subject the product to localized high temperatures, 500 F. for example, while the dryer was at rest. Of course, stopping the operation at any stage prior to completion can only extend processing time with consequent increase in operating cost.

It is therefore an object of this invention to provide a sampling device for removal of test specimens from a rotating vacuum dryer, cone-type, cylindrical drum and/ or tumbler, without interrupting rotation, without breaking vacuum, or without discontinuing or varying any phase of the cycle of operations.

Another object of this invention is to provide a continuous type sampling device for a rotary cone vacuum dryer which eliminates the need for a plurality of evacuated interlocks.

Other objects of this invention are to provide an improved device of the character described which is easily and economically produced, which is sturdy in construction and both highly efficient and effective in operation.

With the above and related objects in view, this invention consists of the details of construction and combination of parts as will be more fully understood from the following detailed description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a front elevational View of a double cone dryer embodying the specimen sampling device of this invention.

FIG. 2. is a diagrammatic view showing the layout for assembling FIGS. 3A, 3B and 30.

FIGS. 3A, 3B and 3C are respective side elevational enlarged views, and partly in section, of the sample removal end, the intermediate 'vapor removal portion and the treatment portion of the dryer.

FIG. 4 is a sectional view taken along lines 44 of FIG. 3B.

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 4.

Referring now in greater detail to the drawings in which similar reference characters refer to similar parts, we show a double cone rotary vacuum dryer, generally designated as A, drive means -B for rotating the dryer, and a sampling device C which extends into the dryer for extracting specimens of product material therein without stopping rotation or breaking vacuum.

The dryer A itself is generally conventional in every respect and includes a central cylindrical portion 12 having outwardly directed conical walls 14 and 16. A charge and discharge port 18 is flange coupled to the truncated end of wall 14 and is opened and closed by means of valve 20. Hollow trunnions or journals 22 and 24 are connected to and extend outwardly from the dryer shell A and are supported within bearing blocks 26 and 28 at each side thereof. The bearing blocks 26 and 28 are mounted upon bases 31 and 32. An annular jacket 30 surrounds the dryer A and is adapted to carry hot mediums such as oil or steam, for heating the material to be dried.

The drive means B comprises a motor-reducer unit 34 which drives trunnion 24 by means of a chain and sprocket enclosed within casing 36. The outboard end of trunnion 24 is journaled upon an outer pipe shaft 38 which is supported within a rotary joint 40, such as a Johnson joint. Hot oil or steam is injected into the dryer jacket 30 through a flexible inlet hose 42 by way of inner concentric pipe 43. The heating medium returns through the annular space between trunnion 24 and inner concentric pipe 43 to exit thereafter through outlet hose 44.

The trunnion 22 at the left hand side of the dryer A interiorly supports a stationary vapor pipe 46 on internal bronze bushings 48. The vapor pipe 46 extends into the interior of the dryer A and is held against rotation by bracket arm 50 which is mounted to base 31. A flanged elbow 52 connects the vapor pipe 46 to an air evacuation means, such as a vacuum pump (not shown), whereby material inside the dryer may be exposed to a reduced pressure. Inside the dryer A, the vapor pipe 46 has a branch pipe 47 whose end has a screen filter 53 attached as shown in FIG. 3C. Suitable seals 55 allow rotation of the dryer A about the vapor pipe 46 while maintaining the vacuum inside the dryer.

The very left hand portion of the system as shown in FIG. 1, includes a solid polished end 54 which acts as a drive shaft for the sampling device C. The end shaft 54 is journaled in a bronze seal housing 56 and is connected to the shaft 58 of a slow speed drive motor (not shown) through coupling 60. A T-fitting 62 is connected between 3 the flanged end 57 of seal housing 56 and a short nipple 64 commumnicating with elbow 52.

The sampling device C includes a tubular housing member 66 which is swaged and silver soldered upon a tapered portion of shaft 54 inside of the seal housing flange 57. Suitable internal mechanical seals are provided to maintain vacuum within the T-fitting 62. A stainless steel wire 68 is wound in a right hand helix which is enclosed and tack welded inside the tubular housing 66 to define a hclicoidal or spiral core. The interior end of the tube housing 66 extends co-axially through the vapor pipe 46 and terminates at the center of the dryer A. As shown in FIG. 3C, the tube housing 66 is rotatably supported within a Tetran bushing 70 at the capped end of the vapor pipe 46. A collar 72 adjacent the right hand end of the tube housing 66, as shown in FIG. 3C, cooperates with a collar 74 on shaft 54 at the left hand end of seal housing 56, as shown in FIG. 3A to maintain longitudinal disposition of the sampling device C on the vapor pipe 46. The right hand end of the tube housing 66 has a semi-cylindrical portion cut away to half-expose the wire screw 68 at 76 and allow it to act as a rotating scoop. Thus, the sampler device C axially projects through the vapor pipe 46 and the scoop end 76 is immersed in product material which is charged into the dryer at approximately 65 percent of its dryer volume. Since the scoop 76 is buried within the product, test samples may be extracted by rotating the drive shaft 54 counterclockwise, whereby the material is drawn along the wire screw 68 within tube housing 66.

Referring now to FIG. 3A, a semi-cylindrical portion of the tube housing 66 is cut away within the T-fitting 60 to define a port 78. The material is thus discharged into glass slight container 80 which is connected to the bottom of the T-fitting 60 by way of a union 82. A valve 84 is coupled to the lower end of sight tube 80, and a T-fitting 86, whose leg is in communication with an air evacuation system, acts as a lock. Immediately below the lock 86 is a second glass container 88, and a valve 90 is mounted at its lower end.

When a suitable sample has been extracted and deposited in sight class 80, valves 84 and 90 both being closed, glass container 88 is evacuated through the branch leg 87. Valve 84 is now opened so as to discharge the sample into container 88. Next, valve 84 is closed and container 88 brought up to atmospheric pressure. Valve 90 is then opened to discharge the sample entirely from the device. Valve 90 is closed again and glass container 88 evacuated for the next test specimen.

Although not an integral part of the instant invention, the other accessories for cone dryer operation are fully compatible with the sampling device C herein described. For example, the branched vapor pipe 47 with its screen filter cap 53 enables the vapor to be drawn from the material being dried without pulling particles into the vacuum system. Also included in the operating accessories is a nitrogen feed line 92 which extends through the vapor pipe 46 and is adapted to bathe the product in an inert atmosphere. A vacuum gage line 94 extends from a osition within the branched line 47 back through the vapor pipe 46 to a fitting 95 on which a suitable vacuum gage may be mounted. A thermocouple 96 projects into the dryer A just below the scoop end 76 of the sampling device C and is drawn out through the vapor pipe 46 at a position 97 adjacent the bracket arm mount 50.

As is apparent from the foregoing description, the sampling device C is operative without interrupting rotation of the drum C and without breaking the vacuum therein. Product materials in the cone dryers are charged to 65 percent of the total dryer volume. Since the scoop end 76 of the sample C projects into the geometric center of the tumbler A, it is buried in the product. Rotating the drive shaft 54 by a motor or by hand in a counterclockwise direction causes the right hand helical wire screw 68 to extract product material from the batch. Conversely, rotation of the screw 68 in a clockwise direction throws any material within the tubular housing 66 back into the drum A to insure fresh sampling at all times. Extracted samples are dropped into the sight container 80 from the inverted port 78 in the housing 66 adjacent the T-fittings 60. After the container 88 has been evacuated through the T-fitting vacuum lock 86 with valves 84- and 90 closed, valve 84 is opened to permit its content to fall into the sight container 88. Valve 84 is then closed, the container 86 brought up to atmospheric pressure, and valve 90 opened to permit removal of the test specimen. Valve 90 is then closed and the container 88 evacuated preparatory to extraction of another sample.

Although this invention has been described in considerable detail, such description is intended as being illustrative rather than limiting since the invention may be variously embodied, and the scope of the invention is to be determined as claimed.

What is claimed is:

1. In a rotary vacuum dryer having hollow trunnions including a vapor pipe concentrically extending through one of the trunnions to apply vacuum to the dryer interior, a sampling device comprising extraction means projecting through the vapor pipe into the dryer for withdrawing specimens of product material therefrom at selected intervals, and an air lock positioned with respect to said extraction means to receive and permit removal of extracted samples from the dryer without breaking vacuum thereto, said air lock including a T-fitting coupled to the distal end of said vapor pipe and having a downwardly projecting leg thereon, spaced valve members in said leg, and means for evacuating the zone between said valve members.

2. The invention of claim 1 wherein the zone intermediate the valve members is transparent for viewing the sample of material therein.

3. The invention of claim 2 wherein the zone above the uppermost of said valve members is transparent for viewing the sample deposited from tubular member.

4. The invention of claim 1 wherein said extraction means is axially fixed with respect to said trunnions and rotatable therein, and means for rotating said extraction References Cited UNITED STATES PATENTS 583,792 6/1887 Dupin 73421B 661,568 11/1900 Walter 3492X 2,113,009 5/1938 Tears 73421BX 2,864,254 12/1958 McDonald et a1. 73-424 3,021,202 2/1962 Peirce et al. 214l7.4X 3,206,981 9/1965 Jameson 7342lB FREDERICK L. MATTESON, 1a., Primary Examiner H. B. RAMEY, Assistant Examiner US. Cl. X.R. 

